Brake Disc Caliper problems of the 2001 Mitsubishi Mirage

I purchased a new Mirage from a dealer in 2001. I might have had about 53,000 miles on the car when I started having brake problems. I decided to look into it after I had my first accident, in which I ended up rear ending someone. I got new tires and had the damage repaired. About a month later, I had another accident resulting in rear ending someone. The car was making funny noises when I stopped. I took the car to a mechanic who said my brake pads were worn completely through, as a result of my calipers failing to release, which also wore my rotors our. In addition, he said the wrong size calipers were on the car (they were the original set). I was shocked. It was recommended that I do not drive the car another mile before getting new pads, rotors, and calipers. I was furious--I couldn't afford the entire job, so I had the brake pads replaced and immediately took the car to a Mitsubishi dealer for a second opinion. They said my calipers were fine and my rotors just needed to be shaved. About a month later, I rear ended someone else. I took my car back to a dealer and had the brakes inspected. They said they look fine. I've been driving for 7 years with no prior accidents, then I get 3 in a row. My insurance is through the roof. I drive extra slow with plenty of space between me and the next car. I don't know when my brakes will work properly and they keep telling me they are fine. Today, I took my car into the dealer for a brake inspection--the noise and vibration is very noticeable--and guess what they said--your brakes are fine. I don't know what else to do or who can help me.